A seatbelt assembly is a type of harness system designed to restrain an occupant of an automobile or other motorized vehicle against inadvertent movement that may result, for example, from an abrupt stop or sudden impact with a foreign obstruction. Conventional seatbelt assemblies (also referred to as “safety belts”) employ a belt buckle or like element, which is located inboard from the occupant seating position, for engagement with a mating latch plate or fastener, generally provided outboard from the occupant seating position. Engagement of the latch plate with the belt buckle positions a belt strap or webbing across the body of a seated occupant for restraining the occupant against abrupt movement from the seat.
Due to the nature and magnitude of the loads on the safety belt during vehicle impact, the seatbelt assembly has traditionally been mounted directly to the vehicle structure, generally utilizing a three-point attachment configuration. In such arrangements, the belt webbing is normally attached at one end to the vehicle side structure by a belt retractor that is rigidly mounted thereto. The webbing extends upwardly along the vehicle side-structure, passing through a support member, such as a D-ring, mounted near the top of the B-pillar. The strap then extends downward, and is anchored at a second end to the floor pan or side structure adjacent to the retractor.
The latch plate is supported on the belt webbing, adapted to slide between the support-ring and the end of the strap anchored to the vehicle structure. The belt buckle, on the other hand, is conventionally mounted to the vehicle structure, such as the floor pan or tunnel, by a buckle strap which extends through a gap between the bottom cushion and either the middle console or the back cushion of the seat. In a two-point attachment configuration (e.g., wherein a lap belt is provided), the second end of the belt webbing is adjustably secured directly to the latch plate, thereby eliminating the third attachment point.
It is also reasonable to mount portions of the seatbelt assembly directly to the vehicle seat assembly so that the seatbelt anchors maintain a more consistent relationship to the occupant when the seat position is adjusted. By way of example, the seatbelt retractor may be affixed directly to the seat platform (i.e., the base of the seat frame). The strap then extends upwards along the back-frame of the upper seat cushion and passes through a guide or upper support member mounted at the top of the seat frame, adjacent the head rest. The strap then extends downward, and is anchored to the seat frame adjacent to the retractor. With today's seatbelt systems, it is more common to mount the inboard anchor to which the buckle attaches to the seat structure. Many seatbelt implementations also mount the outboard lower anchor to the seat structure. For these implementations, the anchor is typically attached to the portion of the seat structure that moves fore-aft when the seating position is adjusted, but could also be mounted to the portion of the seat frame that moves up-down when the seating position is adjusted.
The seatbelt retractor is intended to increase comfort for the vehicle occupant by allowing the webbing to pay out under relatively low loads, enabling limited movement of the restrained occupant. The retractor is biased to keep the webbing relatively taut about the vehicle occupant, and includes a locking device to lock the retractor against webbing pay out at low loads under certain extraordinary conditions. In addition, energy absorbing webbing payout features have been introduced to control the amount of loading that a seatbelt can provide during occupant restraint in an impact, and act to pay out the webbing at predetermined force levels.
In recent years, “pretensioners” have been introduced to actively tighten the seatbelt strap about the vehicle occupant in the event of a sensed triggering condition, such as the onset of an impact event. A pretensioner operates to rapidly draw in a length of webbing, which takes up any slack that may have developed in the belt. Most pretensioners use pyrotechnically generated expanding gas to drive a piston that is attached to the belt webbing. As the piston translates, it pulls the belt webbing, increasing tension around the occupant, in order to maximize the effect of the seatbelt protection and help to more correctly position the vehicle occupant in the seat.
Many vehicles, as part of an overall occupant restraint system, may also include one or more inflatable airbag devices. Inflatable airbag devices, which are now more commonly referred to in the art as Supplementary Restraint Systems (SRS), Air Cushion Restraint Systems (ACRS), or Supplemental Inflatable Restraint Systems (SIR), are originally equipped in almost all present day automotive vehicles. Airbag devices are generally located in the passenger compartment of automotive vehicles, and act as a selectively deployable cushion capable of attenuating occupant kinetic energy. Most airbags are also designed to minimize inadvertent movement of the occupant to eliminate involuntary contact with the interior structure of the automobile.
Traditional airbag devices comprise an inflatable airbag module stored behind the vehicle instrument panel (e.g., for passenger-side airbags), mounted to the steering wheel hub (e.g., for driver-side airbags), or housed within a vehicle seat assembly, side door trim, or headliner trim (e.g., for side-impact airbags). A plurality of sensors or similar devices is strategically located throughout the automobile to detect the onset of a predetermined triggering event. The sensor(s) responsively activates an inflation device, internally located in the airbag module, to produce a flow of inflating gas into an inflatable, relatively unstretchable cushion (i.e., an airbag cushion), also located within the airbag module. The inflating gas causes the airbag cushion to be deployed into the vehicle passenger compartment, toward the vehicle occupant.